Heavier Bullets in AR

[piston10]

My KAC shoots 55's fine, my aero likes 75 and will be trying some 77's. It shoots 3-4" groups with 55's also.

 

[Blitzfike]

I have an AR with a 1-7 twist and it shot so horribly (6 in groups at a hundred yards from a rest) that I consigned it to the safe until I convert it to 300 AAC. I'm used to 3/4" groups with my home made 57 grain bullets out of my other AR. I guess I'll try some of the really heavy bullets in it and see what it does. Thanks for the info, especially the link to twist rate/bullet selection.

 

[dennishoddy]

I had the same issues with a .243WSSM upper I bought.
I specified 1-10 twist as I wanted it for a varminter using 55 grain.
6" groups were the best I could get out of it.
Had some 100 grain bullets at home, so I loaded up a dozen and found it shot like a laser.
Doing the old cleaning rod method for determining twist rate, found I actually had a 1-8.
Got some 80 grain to load up to see if it still holds its accuracy.

 

[SMS]

Finally got to test out some heavier bullets today. I tried XM-193 55gr and SSA 69gr HPBT. Surprisingly, there was little, if any measurable difference in POI between the two using my standard 50 yard zero. Pretty windy, but mostly from the 6'oclock so I was a little higher at 100 than I should be.

1/7 rate, 14.5 bbl using a 2MOA 1XAimpoint at 100 yards, unsupported bench...

XM-193: 1.9"



69gr HPBT: 1"



As windy as it was, I had a go at 300 with both rounds and everything landed within 6" of the bull, in 6-7" groups…that's "minute of barn door" enough for me with a QCB configured rifle.

 

[DRC458]

Dug through the shelves over my reloading bench. I knew I had some Sierra 63 grainers. Found out I had some 60's, 65's, and 70-grainers as well. Guess I'll start there and see what happens! Something's gotta' work!

 

[Mr.Glock]

Curious? Are you shooting of a bench with bags? Or?

 

[SMS]

Dug through the shelves over my reloading bench. I knew I had some Sierra 63 grainers. Found out I had some 60's, 65's, and 70-grainers as well. Guess I'll start there and see what happens! Something's gotta' work!

At least you'll have fun experimenting!

 

[DRC458]

Curious? Are you shooting of a bench with bags? Or?

Bench with bags.

 

[DRC458]

At least you'll have fun experimenting!

Yes, I will! I've got the time to do the reloading, but it looks like I may have to wait on Mother Nature to get to the range!

 

[HiredHand]

What powder(s) do you guys like to use with the heavier projectiles? You don't have to give charge weights.